Rear brakes not working

[Chris142]

Originally Posted By: willix
If you get fluid out both rear bleeders, As unlikely as it is, the only other thing, its crazy to think all for pistons are seized...Its silly to think. Did you do a side by side comparison with the shoes new & old to see if there are any differences? do you have the shoes ajusted for a very slight drag when not applied?
Ya I adjusted the shoes up them off 2 clicks. Parking brake feels great.

With the drums off the shoes do go out when I step on the brake pedal. Ya I checked the shoes(still have the old ones) only difference is new vs used/worn out

I checked it tonight..........Still no rear brakes.

 

[defektes]

I am curious to what you find. As my 94 has no rear drum brakes unless I put my entire weight on the pedal.

 

[Smoky14]

Have you slammed the brakes on in gravel to see if they lock up?

Common sense tells me if the shoes move and contact the drum...they are working. Rear drums are not the most efficient but jeeze.

 

[Chris142]

Originally Posted By: Smoky14
Have you slammed the brakes on in gravel to see if they lock up?

Common sense tells me if the shoes move and contact the drum...they are working. Rear drums are not the most efficient but jeeze.
The fronts will easily lock up even on pavement. I can be driving on Asphalt in 1st gear, push on the brake pedal and the gas at the same time. Fronts lock up and skid but the rears keep pushing the Jeep down the rd with the fronts skidding.

 

[Gary Allan]

Quote:
While it seems it would work that way, in my experience that hose caused the brakes to not work at all...even though you got fluid, it was insufficient to actuate both wheel cylinders..the hose had less than a needle sized hole visible through its interior.


I missed this. While I can't quite figure why it would not eventually fill both wheel cylinders (I'd figure that the MC could not travel far enough without moving xx cc's of fluid) I can't quite figure anything else.

I'd eliminate the combo valve if I could for a test. If the condition is still there, start replacing lines.


You test the proportioning valve by opening one bleeder in the back and having a hose (on the open bleeder) submerged in clean brake fluid. With someone at the wheel and pushing the pedal, the dash light should illuminate since there will now be an imbalance front to rear. You're only testing the differential pressure switch in this test. That's from the 99 FSM.


One last oddball factoring thing. Open a front bleeder and see if the rears start working normally. What would that do? It would eliminate the front fluid displacement (or lack of it) from stopping the MC piston from moving far enough. How could this possibly happen? Got me swinging.

 

[willix]

The hoses can get a pin hole causing a separation and the fluid pushes into the plies closing the hose off inside futher down. Or, the rusted mounting bracket or swedged fitting end can rust restricting or choking off the hose.

 

[Gary Allan]

Rust shouldn't be an issue, it's a 2002. The rubber pulling an anti-parastalic dead end is interesting.

 

[deeter16317]

From what I remember of this thread, the only things he HASN'T replaced are the steel lines and the proportioning valve. He indicated to me that he already replaced the rubber hose, the wheel cylinders, and the master cylinder...

The only other thing I could imagine it could possibly be is a defective ABS unit??? 2002 should have at least rear ABS IIRC?

 

[Chris142]

Originally Posted By: deeter16317
From what I remember of this thread, the only things he HASN'T replaced are the steel lines and the proportioning valve. He indicated to me that he already replaced the rubber hose, the wheel cylinders, and the master cylinder...

The only other thing I could imagine it could possibly be is a defective ABS unit??? 2002 should have at least rear ABS IIRC?
The Prop valve was the first thing I replaced. No ABS on this Jeep. Was not available in 02 with the D44 rear axle and 3.73 gears.

 

[deeter16317]

Originally Posted By: Chris142
The Prop valve was the first thing I replaced. No ABS on this Jeep. Was not available in 02 with the D44 rear axle and 3.73 gears.



Hmmm? I figured rear anti-loc was standard on all DCX "rear wheel drive" vehicles since the early 90s.

Short of it being a defective new part, or a piece of something in one of the lines...I'm out of ideas.

 

[Vikas]

I would get another prop valve; new part can be faulty.